Administration of a timed-release preparation of glipizide will result in a lower incidence of hypoglycemia among elderly type II diabetic subjects who omit the midday meal compared with administration of an equal dose of glyburide. Will study 52 type II diabetic patients between the ages of 55 and 75 after oral administration of placebo, low dose oral sulfonylurea, & high dose oral sulfonylurea during a nine hour protocol which will include breakfast but omit lunch. Biostatistician ONLY.